On Thu, 9 Dec 2010 07:55:36 -0800, Edward Jaffe <[email protected]> wrote:
>On 12/9/2010 4:19 AM, Tony Thigpen wrote: >> It was my understanding that addresses with bit 31 "on" (xxxxxxxx >> xxxxxxxx 1xxxxxxx xxxxxxxx) are considered invalid. This was imposed due >> to the convention of using the high-bit of a (32 bit) register as a >> flag. So, we can use storage below the 2 GB line or above the 4 GB line, >> but not between them. >> >> Secondly, if using IARV64, you will never receive storage that includes >> this 'invalid' area. > >Not unless you code USE2GTO32G=YES. But note that (as far as I know) USE2GTO32G is an undocumented parameter that is not part of the intended programming interface. -- Walt Farrell IBM STSM, z/OS Security Design
